It is generally found in the coffee industry that consumers associate quality coffee with a good coffee aroma. If a coffee product lacks coffee aroma, consumer perception of the product is adversely affected. Unfortunately, soluble (or as it is commonly known, instant) coffee after drying is almost entirely aromaless. For this reason, it is conventional to trap coffee aromas which are given off during the processing of the soluble coffee and to later reincorporate these aromas into the soluble coffee.
The usual way of reincorporating the aroma is to first capture the aroma into a substrate such as an oil or emulsion. Suitable procedures for carrying out the capture of the aroma are disclosed in, for example, U.S. Pat. Nos. 3,823,241, 5,030,473, and 5,222,364 but many other techniques are known. Usually a coffee oil or an emulsion of coffee oil and coffee extract, is used as the substrate. The aroma-containing substrate is then usually sprayed on the soluble coffee powder prior to the coffee powders being filled into containers, which are then sealed. Unfortunately, with the substrates conventionally used, either the incorporation of the aroma into the substrate is too good (resulting in inadequate release of the aroma), or aesthetically unappealing oil slicks form on the coffee surface, or both. This has lead to the search for other ways of incorporating the aroma.
The formulation of coffee oil into microemulsions has been suggested; for example in U.S. Pat. No. 4,835,002. However the microemulsions described in this patent require the use of surfactants and alcohols in order for them to form. Unfortunately these sorts of ingredients should be kept to a minimum in foodstuffs and should not be present at all if the product is to be considered 100% coffee. Therefore these microemulsions are not suitable for use as coffee aromatizers. Further, there is no mention of the incorporation of coffee aroma into the microemulsion system; merely coffee oil.
Therefore there is still a need for a system for reincorporating coffee aroma into a soluble coffee product which provides a burst of aroma once the coffee product is dissolved in water, but which produces little or no oil slicks on the surface of the coffee.